As is knowledge of technicians on the matter, the current state of the art is composed of various cooling system configurations. Among these configurations, and based on the scope of the subject invention are the following ones that comprise at least two independent lines of evaporation/suction and therefore at least two evaporators for working at different pressures acting in different temperature ranges.
In this scenario, particular reference is made to Patent PCT/BR2011/000120 where are described at least two refrigeration systems settings of at least two independent lines of evaporation/suction. One of these embodiments foresees the use of a reciprocating compressor whose compression mechanism (in particular, the entire valve assembly) is specially modified to have two separate lines evaporator/suction, and comprise expedients to select/enable of temporary mode, only one of the two lines of evaporation/suction. Another embodiment provides the use of a reciprocating compressor comprising a compression mechanism is essentially conventional and comprises the addition of a fluid selector device (three-way valve/two positions) able to select, on a temporary basis, one out of the two lines of evaporation/suction, this allowing the fluid communication with the compression mechanism.
Additionally, although checks that the Patent Document BR1020140072543 describes and illustrates at least one embodiment said fluid selector device originally designed on Patent PCT/BR2011/000120. Furthermore, is expected also the possibility of installing said fluid selector device inside the suction acoustic filter reciprocating compressor.
On the other hand, it has also knowledge of the refrigeration system described in Patent document U.S. Pat. No. 5,531,078, which are provided two rows of evaporation/suction derived arranged evaporators in series and arranged to configure a fractional evaporation system, where part of the refrigerant (portion which has exchanged heat in the first evaporator review) can be returned to the compressor without the need to move the second evaporator. In the embodiment described in that document patenting U.S. Pat. No. 5,531,078, selecting one among the two rows of evaporation/suction is directly performed by means of a valve “ON/OFF”, which in pressure differential function, cooperates with a check valve.
According to the embodiment proposed on Patent document U.S. Pat. No. 5,531,078, “ON/OFF” valve, which is arranged externally to the compressor is directly linked to the line of evaporation/suction of the first evaporator, whereas the check valve, which is disposed inside the compressor, it is linked both to the line of evaporation/suction of the first evaporator (so as to obstruct its counter flow towards the line of evaporation/suction of the second evaporator) and the line of evaporation/suction of the second evaporator (to prevent or enable its flow into the compressor compression mechanism). Thus, according to Patent document U.S. Pat. No. 5,531,078, simple switching of the operating state of the valve “ON/OFF” is able to select, directly or indirectly, from the two lines of evaporation/suction.
However, and as is common for an expert skilled in the art see, the cooling system described in patenting document U.S. Pat. No. 5,531,078 presents technical aspects for improvement/optimization, among which you can highlight: i) the use of two lines evaporation/hermetic suction, which impairs the lubricating oil return; and ii) the technical difficulty of mounting a check valve directly on a pipe where pressurized fluid circulates.
It is based on the teachings of the patent documents PCT/BR2011/000120 and BR1020140072543, and aspects for improvement/optimization in existing Patent document U.S. Pat. No. 5,531,078, which comes to the present invention.